Current stroke hand rehabilitation overlooks sensory deficits, even though sensory deficits hinder motor recovery. Thus, we have developed a novel sensory stimulation, Therabracelet, in which a wristband applies imperceptible vibration to wrist skin to immediately enhance hand sensation and dexterity, facilitate plasticity, and enable home use to increase the treatment dose substantially beyond typical clinic visits. The objective of this proposal is to determine if continuous use of TheraBracelet in the home has a clinically meaningful effect. The career development objective is to build expertise in assessing neural plasticity underlying stroke recovery induced by sensory enhancement. In a double-blinded randomized controlled trial, chronic stroke survivors with moderate hand impairment will wear the TheraBracelet device on the paretic wrist for 8 hours/day every day during their normal daily activity for 1 month, coming to the laboratory for weekly evaluation and for 1- month follow-up evaluation. The device will deliver vibration (treatment) or no vibration (control). Double- blinding is possible because the treatment vibration is imperceptible (i.e., subthreshold). Aim 1: Determine the effect of in-home use of TheraBracelet on neural plasticity. Hypothesis: TheraBracelet induces neural plasticity. The primary measure is the extent that sensory input modulates the primary motor cortex, using the paired associative stimulation protocol with TMS immediately preceded by electrical median nerve stimulation. Secondary measures are cortical connectivity and grip-related spectral power change assessed using EEG. Secondary analyses will include individual factors associated with responsiveness to TheraBracelet and longitudinal analysis of outcomes to determine the way effects accumulate over time. Aim 2: Determine the effect of in-home use of TheraBracelet on hand function. Hypothesis: The immediate improvement in hand function with TheraBracelet leads to more use of the affected hand and arm in the home, resulting in functional recovery. The amount of the paretic arm use in daily living will be assessed using accelerometers. Clinical hand function will be assessed using the Wolf Motor Function, Box and Block, and Action Research Arm Tests. In addition, biomechanical hand grip control will be assessed by the ability to direct grip force, excess grip force used, and kinetic/kinematic response to perturbation of a gripped object to describe dynamic feedback control. Impact: This research will elucidate neural plasticity and behavioral effects induced by wearing a novel sensory stimulation device throughout daily living, along with determining likely responders and treatment duration effects. This research will guide the design of a future R01 to investigate the clinical utility of TheraBracelet for post-stroke hand motor recovery. This research is translational as stroke survivors can easily use this low-risk vibrating wristband. This research supports the COBRE major themes of neuromodulation, translation of an innovative treatment device, and using multidisciplinary datasets toward individualized intervention. Enhancing hand function should increase stroke survivors? independence and quality of life.